tubafour wrote:Sorry if this is a dumb question, but does the compensating/non-compensating thing apply to tubas as well? It seems like, if it did, then the low range would be much easier to get in tune than it is for me.
Not a dumb question at all. Besson believes that tuba should also have automatic compensating valves.
We should adopt a broader definition of "compensation", and I think that will help. For me, compensation is something you do to correct for the sharpness that results from using valves in combination. Again, when you press the fourth valve, you've lengthened a BBb instrument into an F instrument, and the other valves are no longer long enough to serve their usual purpose. Donald Stauffer called this the valve swindle. Thus, the 2-4 low B is a bit sharp, and the notes in the very low register below low F are all much sharper than they would be with valves of the proper length.
That said, there are several ways to attack the problem. You can use alternative valve combinations for those notes. You can pull slides. You might employ some sort of trigger, which may actuate like a valve but really is just an easier way to pull slides. You might use a fifth valve. And you might avoid the low register issue altogether by playing those tones as false tones (in which case the valves are the proper length and the pitch is flexible enough in any case). Finally, you can use automatic compensation as designed by Blaikley and used originally by Boosey and now standard on high-line euphoniums and British tubas.
Each method has strengths and weaknesses, of course. The problem with automatic compensation is that the length of the tubing is not the only thing that affects intonation. The taper design is at least as important as length. Thus, if the taper design isn't just right, throwing compensation on it won't help. If the partials are unusably out of tune, compensation is just more clutter. I would add that this isn't easy to achieve. I don't know of an instrument that plays all the normally used partials in tune, compensated or not.
The other disadvantage to compensation is that it adds a lot of twists and turns to the large amount of straight tubing to the instrument in the low register. On euphoniums, the bore is relatively bigger compared to the length of the bugle than on a tuba, and thus all that straight tubing on a tuba has more negative effects on the way the instrument blows. (If we scaled a euphonium up to a tuba, the bore would be huge. Fred Young suggested such scaling should take place using the dimensionless ratios, such as the ratio of bore to bugle length. A BBb tuba is twice the length of a euphonium, and should therefore have twice the bore to be in scale with it. I don't think we want to blow instruments with a 1.16" bore!) The bottom line is that many four-valve compensating tubas have been thought to be stuffy in the low register. And Blaikely compensation has two complete sets of ports on each valve, making the valve substantially longer and heavier than uncompensated valves. It's apparently not a problem for euphonium players, but tuba valves are much larger in the first place.
Another issue is that the notes in the fourth-valve range are rarely played in practice. This is true for euphoniums, too, but it's more true for tubas.
Most tubas use a fifth valve to compensate for incorrect valve combinations. The fifth valve is usually tuned to provide a proper first valve when the fourth valve is in use. Thus, an F tuba with the fourth valve down becomes a C tuba, and the fifth valve is a proper first valve for a C tuba. This corrects the worst of the fourth-valve notes, the whole step right below the low fourth-valve note. On a BBb tuba, this is a low Eb. Many play it 1-2-4 if they don't have a fifth valve, but this is too much compensation and the note is flat. As those combinations use more and more valves, you reach a point where the valves add up to something that's a full semitone sharp, and it works fine (for the note a semitone above the nominal note for the valve combination). The fifth valve is generally design to fill the gap between the low fourth-valve note and the note where fingerings on the four valves line up a semitone high.
For example, an F tuba plays a C on the fourth valve, and the A below it usually works perfectly using the 2-3-4 combination. 2-4 gives you a usable low B, and the fifth valve, used with the fourth, gives you the Bb.
There are, of course, many other fifth-valve strategies.
Thus, the fifth valve approach to compensation has some advantages over Blaikley compensation, in that you don't have as many twists and turns in the valve branches to get through those compensation branches, leaving a more free-blowing instrument (supposedly).
But here's the main reason why tubas don't usually have Blaikley compensation: They never became popular. They have been available for over 100 years, but most players outside the current and former British empire prefer what they get from tubas that use additional valves for compensation. People select tubas on a range of issues, with sound and response being foremost. If the intonation is manageable, the instrument will be acceptable is the sound and response is what the player wants. Thus, the market has spoken.
Rick "whose tubas' intonation problems are not related to the valve swindle" Denney
